As a crucial primary nears, track the California races that could flip the House

California’s June 5 primary will set the course for which congressional districts will be battlegrounds — or missed opportunities — this fall. With just over two months to go, we’ve updated our rankings of the most competitive contests in the state. The stakes in the midterm elections couldn’t be higher: control of the U.S. House. Democrats consider 10 Republican-held districts here to be battlegrounds and can’t win the House without winning at least a few of them.

Retirements in Southern California have created two open-seat races that could make that task a bit easier. On the other hand, the Republicans running to replace them might fare better against crowded fields of Democratic hopefuls, many of whom are seeking office for the first time. California’s top-two primary system could threaten Democrats, too, as Republican candidates could grab the top two spots in certain races and advance to the general election, shutting Democrats out.